Flexible ISFET Biosensor Using IGZO Metal Oxide TFTs and an ITO Sensing Layer

Smith, John E.; Shah, Sahil; Goryll, Michael; Stowell, John; Allee, David R.

doi:10.1109/jsen.2013.2295057

Cited by 61 publications

(35 citation statements)

References 5 publications

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“…For a-IGZO, higher temperatures (i.e. above 400 o C) are known to deteriorate the TFT performance with the films being amorphous till about 400 o C and reported to be polycrystalline above 500 o C. 14 The a-IGZO films annealed at 400 o C have reported [1][2][3] to provide the optimum TFT performance. Hence, the annealing temperature of 400 o C was used for processing a-IGZO to study its sensing characteristics in N 2 and O 2 environments.…”

Section: B Electrical Characterizationmentioning

confidence: 99%

“…The use of a-IGZO as the active layer and different dielectrics such asTiO 2 , ITO, SiOx, and TaOx as the pH sensitive layers in TFT based ion sensitive field effect transistors (ISFETs) have been reported. [1][2][3][4] High-k dielectrics (Ta 2 O 5 , Al 2 O 3 , Pr 2 O 3 ,TiO 2 , Er 2 O 3 , and HoTiO 3 etc.) and their stacks to reduce lattice mismatch are used to enhance the pH sensitivity with an objective to achieve the maximum sensitivity of 59.5mV/pH (the Nernstian limit) of field effect sensors.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Low temperature annealed amorphous indium gallium zinc oxide (a-IGZO) as a pH sensitive layer for applications in field effect based sensors

Kumar

Panda

2015

AIP Advances

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The use of a-IGZO instead of the conventional high-k dielectrics as a pH sensitive layer could lead to the simplification of fabrication steps of field effect based devices. In this work, the pH sensitivities of a-IGZO films directly deposited over a SiO2/Si surface were studied utilizing electrolyte-insulator-semiconductor (EIS) structures. Annealing of the films was found to affect the sensitivity of the devices and the device with the film annealed at 400 oC in N2 ambience showed the better sensitivity, which reduced with further increase in the annealing temperature to 500 oC. The increased pH sensitivity with the film annealed at 400 oC in N2 gas was attributed to the enhanced lattice oxygen ions (based on the XPS data) and improved C-V characteristics, while the decrease in sensitivity at an increased annealing temperature of 500 oC was attributed to defects in the films as well as the induced traps at the IGZO/SiO2 interface based on the stretched accumulation and the peak in the inversion region of C-V curves. This study could help to develop a sensor where the material (a-IGZO here) used as the active layer in a thin film transistors (TFTs) possibly could also be used as the pH sensitive layer without affecting the TFT characteristics, and thus obviating the need of high-K dielectrics for sensitivity enhancement.

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Section: B Electrical Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low temperature annealed amorphous indium gallium zinc oxide (a-IGZO) as a pH sensitive layer for applications in field effect based sensors

Kumar

Panda

2015

AIP Advances

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show abstract

“…In addition, ITO can be deposited by DC [65][66][67][68], and RF sputtering at low temperatures [69], making it compatible with polymeric substrates. For these reasons, ITO has been widely used as a transparent electrode in flexible sensors [20,[70][71][72][73][74][75][76][77]. Nevertheless, resistivity values below 5 × 10 -4 Ω cm are not easily obtained for fabrication processes at room temperature [67].…”

Section: Amorphous Oxide Conductorsmentioning

confidence: 99%

Flexible Sensors—From Materials to Applications

et al. 2019

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Flexible sensors have the potential to be seamlessly applied to soft and irregularly shaped surfaces such as the human skin or textile fabrics. This benefits conformability dependant applications including smart tattoos, artificial skins and soft robotics. Consequently, materials and structures for innovative flexible sensors, as well as their integration into systems, continue to be in the spotlight of research. This review outlines the current state of flexible sensor technologies and the impact of material developments on this field. Special attention is given to strain, temperature, chemical, light and electropotential sensors, as well as their respective applications.

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“…Since the NIL process is based on direct mechanical deformation, the resolution of nanostructures is not limited to light diffraction or beam scattering, which are common in conventional nanolithography techniques. Due to its great potential in large format micronano pattern fabrication, NIL has been widely researched and has already been developed from platetype NIL [8] to roller-type NIL [9,10] to meet the need for novel applications in manufacturing flexible transparent conductive materials as a substitute for traditional indium tin oxide (ITO), which is vital in flexible electronics such as flexible display panels [11,12], flexible solar cells [13][14][15] and flexible sensors [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Metal mesh electrode array fabricated by plate-to-roll nanoimprint lithography

Yang

Zhou

et al. 2020

SN Appl. Sci.

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Nanoimprint lithography has long been considered a way of fabricating micronano structures in a high-efficiency manner. Based on this method, various 2D and 3D structures with feature sizes ranging from a few micrometers down to a single nanometer have been demonstrated. Here, we present the mechanical and control system design of recently developed plate-to-roll nanoimprint equipment. To improve the parallelism between the template and the substrate, we propose a three voice coil motor actuated mechanical structure and improved proportion integration differentiation algorithm, which can provide fast response and precise positioning. We used a template with a grooved structure to test the embossing performance. By using the nanoimprint system, an electrode array based on a metal mesh transparent conductive material was fabricated on a flexible substrate, which shows the great potential of this system for the fabrication of flexible devices.

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Flexible ISFET Biosensor Using IGZO Metal Oxide TFTs and an ITO Sensing Layer

Cited by 61 publications

References 5 publications

Low temperature annealed amorphous indium gallium zinc oxide (a-IGZO) as a pH sensitive layer for applications in field effect based sensors

Low temperature annealed amorphous indium gallium zinc oxide (a-IGZO) as a pH sensitive layer for applications in field effect based sensors

Flexible Sensors—From Materials to Applications

Metal mesh electrode array fabricated by plate-to-roll nanoimprint lithography

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